41
FT-847 O
PERATING
M
ANUAL
OPERATION
R
ECEIVER
F
EATURES
N
OTCH
F
ILTER
(DSP)
Unwanted beat notes within the receiver’s IF filter
passband can be effectively removed by utilization of
the DSP N
OTCH
function. The DSP system will detect
the incoming carrier, then automatically center a sharp
notch filter to eliminate the beat note. If multiple beat
notes are present, the DSP will create multiple notch
filters to eliminate them.
To activate the DSP N
OTCH
filter, press the
[
D. NOTCH
] switch; the “
NOTCH
” icon
will appear on the display. To turn this fil-
ter off, press the [
D. NOTCH
] switch again.
Note
: The DSP N
OTCH
filter should not be
used in the CW mode! The DSP system will in-
terpret a CW carrier as being “interference,”
and will notch out the incoming signal. There-
fore, as you tune the CW portion of the band
with the N
OTCH
filter on, CW signals will ap-
pear for a moment, then disappear as they are
notched out.
CW R
EVERSE
While operating on CW, occasionally you may encoun-
ter interference situations which cannot be resolved
by switching to a narrower filter or by adjustment of
the IF S
HIFT
control. And there sometimes are operat-
ing situations requiring a mode change from, for ex-
ample, LSB to CW; if the wrong “sideband” is uti-
lized in the CW mode, the other station may not be
easy to find.
The FT-847 can be quickly configured, so as to avoid
these problems, to utilize either “USB” or “LSB” car-
rier injection in the CW mode. To do this, while in the
CW mode, just press the [
CW
] switch momentarily.
The “
CW
” icon glows steadily for USB-side injec-
tion, while the “
LSB
” icon will appear to the left of
the “
CW
” icon for LSB injection. This system allows
instantaneous recognition of the current injection mode
selected for CW use.
Referring to example
A
, note the
presence of both a desired signal
and interfering signal. By switch-
ing sidebands (example
B
), note
how the interfering signal has been
avoided through selection of the
opposite sideband.
Note
: W h e n s i d e b a n d s a r e
switched, all aspects of CW
operation are switched at
once, including the trans-
mitted CW carrier and the displayed frequency.
This avoids the necessity of making multiple ad-
justments so as to align the receiver and trans-
mitter sections for proper operation.
Содержание FT-847
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